Agatha is one of two surviving criminals from a previous generation, and quite likely the one guilty of wiping it out. She is also responsible for orchestrating the nightly raptor attacks and evading Sentience's attempts at punishing her for these actions, leading to the warden placing a bounty over her head. She was finally apprehended by inmates Zero Kiryuu, Saix, and Seifer Almasy.

Recent appearances prove her to act childlike and cruel and always accompanied by a robot escort, having been "taken care of" by Sentience.

Agatha possesses an affinity to the element of earth.